Compliant collet assembly

Abstract

A collet assembly for picking and placing a disc pack in an automated assembly process, the collet assembly having a retractable cylinder that extends to spreadingly engage a segmented collet against a lifting surface of the disc pack to support the disc pack during a lifting operation. The collet assembly is positioned by a positioning assembly to an engaging position adjacent the disc pack. A locking cylinder supports a lower pad and an upper pad on opposing sides of a flange portion of the collet assembly, to provide a fixed mode in a retracted position of the locking cylinder wherein the collet assembly position is fixed relative the positioning assembly, and to provide a compliant mode in an extended position of the locking cylinder wherein the collet assembly is free to compliantly float in a two-axis plane relative to the positioning assembly.

What is claimed is: 
     
       1. A head and disc assembling apparatus for assembling a disc drive from a plurality of component parts, the component parts comprising a disc drive motor having a plurality of discs attached thereto to form a disc pack, and the head and disc assembling apparatus comprising a positioning assembly for selectively positioning the disc pack, the positioning assembly supporting a gripping collet comprising: a support plate attached to the positioning assembly;   a collet body supported by said support plate, comprising: an annular passageway; and   a flange portion disposed adjacent said annular passageway;     a cylinder supported at a proximate end of said collet body, said cylinder having an extensible shaft moveable between a retracted and an extended position;   a segmented collet supported by a distal end of said collet body, wherein said segmented collet is spreadably movable to grip the disc pack;   an actuating pin supported by said cylinder and slidingly disposed in said annular passageway;   a tooling ball attached to a distal end of said actuating pin, said pin clearingly disengaging said segmented collet in a retracted position of said shaft, and said pin spreadingly engaging said segmented collet in an extended position of said shaft to grip the disc pack;   a clamping assembly for clamping said collet in a fixed mode relative said support plate, and for unclamping said collet in a compliant mode relative said support plate, said clamping assembly comprising: a locking cylinder having an extensible shaft;   an upper pad disposed between said locking cylinder and said flange portion of said collet body; and   a lower pad supported by a distal end of said locking cylinder shaft and opposingly engaging said flange portion of said collet body in the retracted position of said locking cylinder.     
     
     
       2. The apparatus of claim 1 wherein the disc pack has a lifting surface forming an aperture, and wherein said segmented collet has a tip disposable in the aperture to pressingly engage said lifting surface when said tooling ball spreadingly engages said segmented collet. 
     
     
       3. The apparatus of claim 2 wherein said collet body, in the compliant mode, is compliantly movable relative to said support plate, and wherein a plurality of roller bearings are supportingly disposed between said support plate and said collet body. 
     
     
       4. The apparatus of claim 3 wherein the gripping collet further comprises a center race between said collet body and said support plate, and wherein the gripping collet further comprises: a first plurality of roller bearings interposed between said center race and said collet body; and   a second plurality of roller bearings interposed between said center race and said support plate.   
     
     
       5. The apparatus of claim 4 wherein said center race further comprises a first groove, and wherein the gripping collet further comprises: a second groove in said support plate disposed in a parallel plane and in a direction orthogonal to said first groove; and   a ball bearing disposed in said first and second grooves.   
     
     
       6. The apparatus of claim 5 wherein said center race further comprises a third groove in a parallel plane and in a direction orthogonal to said first groove, and wherein the gripping collet further comprises: a fourth groove in said flange portion of said collet body disposed in a parallel plane and in a direction orthogonal to said third groove; and   a roller bearing disposed in said third and fourth grooves.   
     
     
       7. The apparatus of claim 6 wherein said lower pad is tapered at a portion thereof that pressingly engages said flange portion of said collet body. 
     
     
       8. The apparatus of claim 7 wherein said flange portion of said collet body has a tapered aperture which matingly engages said tapered portion of said lower pad, and wherein retraction of said cylinder matingly engages said tapered portion of said lower pad and said tapered aperture of said flange portion to move said collet body to a selected position in a fixed mode. 
     
     
       9. The apparatus of claim 8 wherein said cylinder shaft has a stop member locked thereon to engage said cylinder to positively limit said shaft travel in the extended mode. 
     
     
       10. A gripping collet comprising: a support plate;   a collet body supported by said support plate, comprising: an annular passageway; and   a flange portion disposed adjacent said annular passageway;     a cylinder supported at a proximate end of said collet body, said cylinder having an extensible shaft moveable between a retracted and an extended position;   a segmented collet supported by a distal end of said collet body, wherein said segmented collet is spreadably movable to grip a member;   an actuating pin supported by said cylinder and slidingly disposed in said annular passageway;   a tooling ball attached to a distal end of said actuating pin, said pin clearingly disengaging said segmented collet in a retracted position of said shaft, and said pin spreadingly engaging said segmented collet in an extended position of said shaft to grip the member;   a clamping assembly for clamping said collet in a fixed mode relative said support plate, and for unclamping said collet in a compliant mode relative said support plate, said clamping assembly comprising: a locking cylinder having an extensible shaft;   an upper pad disposed between said locking cylinder and said flange portion of said collet body; and   a lower pad supported by a distal end of said locking cylinder shaft and opposingly engaging said flange portion of said collet body in the retracted position of said locking cylinder.     
     
     
       11. The gripping collet of claim 10 wherein the member has a lifting surface forming an aperture, and wherein said segmented collet has a tip disposable in the aperture to pressingly engage said lifting surface when said tooling ball spreadingly engages said segmented collet. 
     
     
       12. The gripping collet of claim 11 wherein said collet body, in the compliant mode, is compliantly movable relative to said support plate, and wherein a plurality of roller bearings are supportingly disposed between said support plate and said collet body. 
     
     
       13. The gripping collet of claim 12 wherein the gripping collet further comprises a center race between said collet body and said support plate, and wherein the gripping collet further comprises: a first plurality of roller bearings interposed between said center race and said collet body; and   a second plurality of roller bearings interposed between said center race and said support plate.   
     
     
       14. The gripping collet of claim 13 wherein said center race further comprises a first groove, and wherein the gripping collet further comprises: a second groove in said support plate disposed in a parallel plane and in a direction orthogonal to said first groove; and   a ball bearing disposed in said first and second grooves.   
     
     
       15. The gripping collet of claim 14 wherein said center race further comprises a third groove in a parallel plane and in a direction orthogonal to said first groove, and wherein the gripping collet further comprises: a fourth groove in said flange portion of said collet body disposed in a parallel plane and in a direction orthogonal to said third groove; and   a roller bearing disposed in said third and fourth grooves.   
     
     
       16. The gripping collet of claim 15 wherein said lower pad is tapered at a portion thereof that pressingly engages said flange portion of said collet body. 
     
     
       17. The gripping collet of claim 16 wherein said flange portion of said collet body has a tapered aperture which matingly engages said tapered portion of said lower pad, and wherein retraction of said cylinder matingly engages said tapered portion of said lower pad and said tapered aperture of said flange portion to move said collet body to a selected position in a fixed mode. 
     
     
       18. The gripping collet of claim 17 wherein said cylinder shaft has a stop member locked thereon to engage said cylinder to positively limit said shaft travel in the extended mode.